GlslInstanceMember struct
#include <derCompiler/GlslToCpp.h>
One scalar/vector member of the per-instance std140 block, with its baked byte offset.
The constant-varying analysis reads instance-block members (spriteSize, texRect, palOffset, ...) from the bound uniform block at these std140 offsets, so a per-instance-constant varying can be recomputed on the CPU. The offsets come from the program's block reflection (a batched shader contributes the fields of its instance struct, whose offsets are relative to the per-instance start). Matrix members are omitted (never referenced by a supported varying).